U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2014–1241

Movements of Wild Pigs in Louisiana and Mississippi, 

2011–13
 
Movements of Wild Pigs in Louisiana and 

Mississippi, 2011–13

By Stephen B. Hartley, Buddy L. Goatcher, and Sijan K. Sapkota

Open-File Report 2014–1241

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2014

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ISSN 2331-1258 (online)

Suggested citation:

Hartley, S.B., Goatcher, B.L., and Sapkota, S.K., 2015, Movements of wild pigs in Louisiana and Mississippi, 2011–13: 

U.S. Geological Survey Open-File Report 2014–1241, 11 p., http://dx.doi.org/10.3133/ofr20141241. 
iii

Acknowledgments

The authors would like to thank Dirt Piranha and Goatcher Wildlife for donations of trained capture-dog services and related equipment. Thanks are given to Cannisnia Plantation, Matt Rimmer Farm, Chad Courville of Miami Corp., Judge Edwards and Bill Broussard of Vermilion Corp., 

and local landowners and lessees Dennis Good and Dan Hidalgo, Sr., for providing access to 

study sites. The authors would like to express appreciation to local hunters Daniel Edgar, James 

Aucoin, Shane Boudreaux, Cody Fortier, Calen Mire, Joey Young, Parker Perot, Scotty Dickson, 

Skipper Dickson, Adam Goatcher, Kim Crochet, Brian Haupt, Kody Landry, Noel Bunol, Mike 

Fradella, Michael D. Fradella, Matthew Fradella, and Jonathan Fradella for logistical support 

and valuable advice during field work. Special thanks go to Walter Cotton and Scott Woodriff 

of the U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service and 

Robert “Goose” Gosnell and John Dickson of the U.S. Fish and Wildlife Service for conducting 

field work. Thanks to Dwight LeBlanc of the USDA Animal and Plant Health Inspection Service 

and Dr. Jim LaCour of the Louisiana Department of Wildlife and Fisheries for reviews of the 

study plan and to Drs. Bronson Strickland and Bruce Leopold for their valuable comments in their 

peer review of the report.

v

Contents

Abstract ..........................................................................................................................................................1

Introduction ....................................................................................................................................................1

Methodology ..................................................................................................................................................2

Results ............................................................................................................................................................4

Statistical Analysis ..............................................................................................................................4

Geospatial Analysis .............................................................................................................................6

Discussion ......................................................................................................................................................9

Summary .......................................................................................................................................................10

References Cited .........................................................................................................................................10

Figures

1. Map showing study area and sites of capture and release of wild pigs fitted 

with satellite GPS tracking collars during the 2011–13 study in Louisiana and 

Mississippi ....................................................................................................................................3

2. Graph showing average distance traveled per hour by collared wild pigs and 

average air temperature by season during the 2011–13 study in Louisiana and 

Mississippi ....................................................................................................................................5

3. Graph showing monthly average of distance traveled per hour by collared wild 

pigs during the 2011–13 study in Louisiana and Mississippi ................................................6

4. Radar chart showing average distance traveled by collared wild pigs on an 

hourly basis during 24-hour periods and depicting diurnal effect in movement 

during the 2011–13 study in Louisiana and Mississippi .........................................................7

5. Graph showing regression with a 95-percent confidence band showing average 

distance per hour traveled by wild pigs relative to average air temperature 

during a 24-hour period during the 2011–13 study in Louisiana and Mississippi ..............8

6. Graph showing maximum distance traveled per hour by wild pigs with respect 

to gender and season during the 2011–13 study in Louisiana and Mississippi .................9

Tables

1. Seasonal average distance traveled per hour by collared wild pigs and onsite 

air temperature recorded from hourly monitoring data during the 2011–13 study 

in Louisiana and Mississippi ......................................................................................................4

2. Distance traveled per hour by wild pigs in interval frequency during the 2011–13 

study in Louisiana and Mississippi ...........................................................................................8
vi

Conversion Factors

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

kilometer (km) 0.5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square meter (m2

) 0.0002471 acre 

hectare (ha) 2.471 acre

square kilometer (km2

) 247.1 acre

square meter (m2

) 10.76 square foot (ft2) 

square kilometer (km2

) 0.3861 square mile (mi2)

Weight

kilogram (kg) 2.205 pound avoirdupois (lb) 

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88) unless otherwise noted.

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Time in this report is given as 24-hour military time and is referenced to local time, including (if 

applicable) daylight saving time.
Movements of Wild Pigs in Louisiana and Mississippi, 

2011–13

By Stephen B. Hartley,1 Buddy L. Goatcher,2 and Sijan K. Sapkota1

Abstract

The prolific breeding capability, behavioral adaptation, 

and adverse environmental impacts of invasive wild pigs 

(Sus scrofa) have increased efforts towards managing their 

populations and understanding their movements. Currently, 

little is known about wild pig populations and movements 

in Louisiana and Mississippi. From 2011 to 2013, the 

U.S. Geological Survey investigated spatial and temporal 

movements of wild pigs in both marsh and nonmarsh 

physiographic regions. Twenty-one Global Positioning 

System satellite telemetry tracking collars were installed 

on adult wild pigs captured with trained dogs and released. 

Coordinates of their locations were recorded hourly. We 

collected 16,674 hourly data points including date, time, air 

temperature, and position during a 3-year study. Solar and 

lunar attributes, such as sun and moon phases and azimuth 

angles, were not related significantly to the movements among 

wild pigs. Movements were significantly correlated negatively 

with air temperature. Differences in movements between 

seasons and years were observed. On average, movements of 

boars were significantly greater than those of sows. Average 

home range, determined by using a minimum convex polygon 

as a proxy, was 911 hectares for boars, whereas average 

home range for sows was 116 hectares. Wild pigs in marsh 

habitat traveled lesser distances relative to those from more 

arid, nonmarsh habitats. Overall, results of this study indicate 

that wild pigs in Louisiana and Mississippi have small 

home ranges. These small home ranges suggest that natural 

movements have not been a major factor in the recent broadscale range expansion observed in this species in the United 

States.

Introduction

Wild pigs (Sus scrofa) are a major problem for land 

and resource managers in the United States because of the 

enormous amounts of damage that these animals cause 

to natural and man-made environments. This exotic, 

invasive species is found in large populations on public (for 

example, Federal sites such as national parks and national 

wildlife refuges) and private lands in most States. Their 

high reproductive potential, ability to adapt to numerous 

environments, destructive foraging habits, and potential to 

function as disease vectors make wild pigs a challenging 

and serious threat to environmental, human, and financially 

important (for example, agricultural) resources in the United 

States (Mayer, 2009; Hamrick and others, 2011). 

Kaller and Reed (2010) described wild pigs as the most 

prolific large mammal in North America; with adequate 

nutrition, their populations can double in 4 months. Comer 

and Mayer (2009) reported that wild pigs can reach sexual 

maturity as young as 3 months, and sows have been 

documented to be reproductively active as old as 14 years of 

age. Kaller and Reed (2010) also stated that sexual maturity 

in sows has been observed as young as 6 months; with a few 

sows birthing two litters per year and averaging 6 piglets per 

litter (ranges between 3 and 8 piglets), the population growth 

in many locations is exponential. On the basis of reproductive 

capacity, it has been estimated that wild pig populations can 

completely rebound from a 70-percent population removal in 

2.5 years. Additionally, reducing only adult females up to 90 

percent may not be effective because of the ability of young 

females (6–12 months old) to reproduce (Kaller and Reed, 

2010). 

In Louisiana and Mississippi, populations of wild 

pigs have existed since the 1500s, when Spanish explorer 

Hernando de Soto, who traveled extensively throughout 

the Southeastern United States, brought pigs with his 

expedition (Hamrick and others, 2011). During the European 

colonization of America, domestic swine were allowed to 

range freely on unfenced lands to be recovered for slaughter, 

a common practice in Louisiana and Mississippi. No scientific 

investigation of the genetic composition of Louisiana or 

Mississippi wild pigs exists, with most assumed to be the 

descendants of domestic swine; however, hybrids of domestic 

swine and Eurasian wild boar are evident in several locales 

on the basis of pelage and morphology (Mayer and Brisbin, 

1993). 

1

U.S. Geological Survey.

2

U.S. Army Corps of Engineers.
2 Movements of Wild Pigs in Louisiana and Mississippi, 2011–13

In the early 1900s, Eurasian wild boars (perceived 

by sport hunters as a more desirable hunting quarry) were 

introduced along with domestic swine by game ranchers 

and private hunting groups (Kaller and Reed, 2010). These 

releases extended the range of invasive wild pigs beyond the 

Southern and Western United States (Mayer and others, 2009; 

Kaller and Reed, 2010; Hamrick and others, 2011). Problems 

with wild pigs historically limited to the Southeastern 

States, California, Hawaii, and Texas now extend to many 

Northern States including Michigan, North Dakota, and 

Oregon (Hamrick and others, 2011). As a result, wild pigs are 

widespread throughout much of the United States, and their 

presence has been reported in 47 States. Wild pig damages to 

agricultural and forest lands are documented worldwide (West 

and others, 2009; Kaller and Reed, 2010); however, scientific 

studies of wild pig damages and movements in Louisiana and 

Mississippi are rare.

Even though wild pigs of the Southern United States have 

a prolific breeding capability as they do elsewhere, during the 

Great Depression (approximately 1930–40) and following 

decades, wild pigs were almost eradicated, except in those 

wards, parishes, and counties where government officials and 

local statutes protected pig free-range practices (Mayer and 

Moore-Barnhill, 2009). Wild pig populations have continued 

to increase even with the banning of free-ranging pigs (Mayer 

and Moore-Barnhill, 2009). Another contributing factor in 

wild pig population increases is the illegal release of Eurasian 

wild boar, wild pigs, and even domestic adult swine and 

piglets by hunters and game ranchers for sport hunting (Kaller 

and Reed, 2010). 

Wild pigs are found in a wide variety of habitats in 

Louisiana and Mississippi, including coastal areas ranging 

from tidal marshes along the Gulf of Mexico coast to forested 

uplands in northern parishes and counties (Mayer, 2009). 

They prefer areas that provide access to water, cover, and a 

dependable source of food. In the Louisiana Chenier Plain 

(fig. 1), seasonal, heavy mast crops may often limit wild pigs 

to smaller areas, but human disturbance or lack of resources 

like food and escape cover may be the two greatest factors 

for their dispersal (Comer and Mayer, 2009; Mayer, 2009). 

Some areas where populations of wild pigs have not been 

seen in recent times will suddenly exhibit rooting, wallowing, 

and other signs of their presence (Kaller and Reed, 2010). 

Concurrent with increased dispersal in types of habitats and 

areas occupied by these animals in Louisiana and Mississippi 

has been an increase of types of damage that wild pigs cause.

Elsey and others (2012) conducted a survey of Louisiana 

alligator farmers regarding alligator nest losses and found that 

more than half of the farmers reported losses of alligator nests 

to wild pig depredation. In 1 year (that is, 2011), there were 

590 nests damaged or destroyed on 36 separate properties 

across the State, whereas only 7 nests were lost in all three 

prior surveys combined. Elsey and others’ (2012) survey 

data of wild pigs damaging alligator nests, eggs, and habitats 

suggest loss of tens of thousands of dollars to landowners 

and managers each year. Besides the loss of alligator nests, 

in coastal wetlands of Louisiana and Mississippi, rootings 

of wild pigs impact subterranean flora and fauna while 

restricting the expansion of root zones of trees and plants, thus 

potentially exacerbating coastal erosion and land loss (Kaller 

and Reed, 2010). 

While monitoring other species from U.S. Fish and 

Wildlife Service (USFWS) helicopters during the BP 

Deepwater Horizon oil spill in 2010, wildlife biologists 

observed a problem of wild pigs in coastal Louisiana (B.L. 

Goatcher, USFWS, oral commun., 2010). The wildlife 

biologists observed that invading wild pigs had encroached 

into new areas at an alarming rate, especially since the passage 

of Hurricanes Katrina and Rita, not only into marshland and 

farmland but also into sensitive wetland nesting bird habitat 

(B.L. Goatcher, USFWS, oral commun., 2010). 

In the last 20 years, wild pig populations have expanded 

markedly throughout the Southeastern United States (Comer 

and Mayer, 2009). One explanation of the expansion is 

biological: wild pig populations have reached a critical mass 

and are demonstrating exponential growth as they colonize 

new areas. A second explanation is that much of the range 

expansion that has occurred over the last 20 years is a product 

of human-caused colonization—the illegal translocation of 

wild pigs to establish new populations for hunting (Comer and 

Mayer, 2009). A study designed to monitor the daily, seasonal, 

and annual movements of wild pigs could provide insight 

into which of these reasons for range expansion is more 

likely and could aid in the development of management plans 

for wild pig control. A concerted, disciplined, professional 

approach to wild pig removals is lacking in the Southern 

United States (Comer and Mayer, 2009). From 2011 to 2013, 

the U.S. Geological Survey investigated spatial and temporal 

movements of wild pigs (that is, to better understand wild 

pig behavior) in order to facilitate an effective approach to 

wild pig control efforts in Mississippi and Louisiana; more 

information regarding wild pig populations, their habitat use, 

and movements at a landscape level is needed.

Methodology

Global Positioning System (GPS) satellite hybrid radio 

telemetry devices were attached to 21 wild pigs (weighing 

54–136 kilograms [kg]) that were captured with trained dogs 

and were released at the capture sites (fig. 1). These GPS 

satellite collar devices have an average battery life of 2 years 

at a data collection interval of 1 hour. The GPS satellite 

collar devices collected hourly data including date, time, air 

temperature, and position and transmitted those readings via 

the Iridium satellite until battery life was exhausted or the 

collar fell off. Although telemetry devices were procured 

from two vendors (Lotek and Telemetry Solutions), the 

manufacturers’ claimed 2-year endurance was not achieved. 

None of the transmitters in our study made that milestone, 
Methodology 3

Shreveport

Monroe

Base modified from U.S. Geological Survey digital data, 1:2,000,000

Albers Equal-Area Conic projection

North American Datum of 1983

34°

32°

30°

94° 92° 90° 88°

Study area

LOUISIANA

MISSISSIPPI

EXPLANATION

Capture and release site

CHENIER PLAIN

Baton Rouge

Alexandria

Lake Charles

New Orleans

Figure 1. Study area and sites of capture and release of wild pigs (Sus scrofa) fitted with satellite Global Positioning System (GPS)

tracking collars during the 2011–13 study in Louisiana and Mississippi.
4 Movements of Wild Pigs in Louisiana and Mississippi, 2011–13

with most lasting less than 4 months before going offline or 

falling off. All data from failed systems and from those that 

fell off prematurely were recoverable; this was critical in 

selecting a vendor. Study sites included agricultural, forest, 

and marsh regions in Louisiana and Mississippi (fig. 1). 

The study sites in both States were considered to have high 

densities of wild pigs. This study was conducted over a 3-year 

period.

Statistical analyses of variance (ANOVA) and covariance 

(ANCOVA) were used to determine the relation among 

distance traveled and time of the day, air temperature (degrees 

Celsius [°C]), and solar and lunar phases. Relations of wild 

pig movements due to air temperature within and between 

seasons (spring [Mar.–May], summer [June–Aug.], fall 

[Sept.–Nov.], and winter [Dec.–Feb.]) were analyzed by 

using partial correlations and Tukey’s honestly significant 

difference (HSD) tests. A t-test was conducted to determine if 

significant differences existed in average movement patterns 

between boars and sows. We used a p-value (P) of less than or 

equal to 0.05 to conclude statistical significance. Spatial data 

were analyzed by using Esri ArcMap 10.1, and SAS 9.3 and 

SAS STAT 12.1 (SAS Institute Inc., 2012) were used when 

analyzing higher order ANOVA and multiple comparison tests. 

To control for the effect of outliers, only wild pigs that were 

tracked for more than 3 days were used in the analysis. 

Use of GPS satellite hybrid radio telemetry facilitates 

remote computer monitoring of the movement of wild pigs. 

The “Judas pig” technique is a method in which a wild pig 

is captured and collared with a tracking device and released 

at the site of capture to be relocated at future dates. Through 

the use of this monitoring technique, the Judas pig will reveal 

individual movements and positions on the landscape so that it 

and potentially entire associated sounders (family groups) can 

be located.

Results

Statistical Analysis

We collected 16,674 hourly data points related to date, 

time, air temperature, and position from 21 GPS-collared 

wild pigs (15 boars and 6 sows; 1 barrow was collared 

but not used in data analysis) from August 3, 2011, until 

May 16, 2013. Solar and lunar data, such as sun and moon 

phases and azimuth angles, were collected and analyzed 

by using Pearson’s correlation and regression analysis; 

however, these data did not show any significant relations with 

movements among wild pigs. Table 1 includes the summary 

statistics of distances traveled by wild pigs (separated by 

gender and season) during the 3-year study period. Sow data 

could not be retrieved for fall seasons of 2011 and 2012. We 

found that, on average, the GPS-collared wild pigs traveled 

longer distances in summer and winter of 2011 and 2013 than 

in all four seasons of 2012 (table 1). 

Boars tended to travel more than sows, regardless of 

the season. Sows tended to travel more in summer than in 

winter and spring, whereas boars traveled more in winter. 

Coefficients of variation (table 1) reveal that sows have a 

lower average travel distance during winter but have greater 

variation. This could be due to a few large but infrequent 

distance values. A similar pattern was observed in which sow 

movements were considerably lower in spring and winter 

when average air temperature is below 20 °C (fig. 2). Boars 

did not show any distinctive movement pattern regarding 

seasonal variation except slightly greater activity in winter 

(figs. 2 and 3). Moreover, during all 3 years, average 

movements in fall and spring were less than in summer and 

winter (fig. 2). 

Table 1. Seasonal average distance traveled per hour by collared wild pigs (Sus scrofa) and onsite air temperature recorded from 

hourly monitoring data during the 2011–13 study in Louisiana and Mississippi.

[m, meters; °C, degrees Celsius; CV (%), coefficient of variation measured in percent]

Season Sex Hourly

data points

Distance (m) Temperature (°C)

Mean Standard 

error CV (%) Mean Standard error CV (%)

Spring

(Mar.–May)

Boar 3,061 90.47 5.16 315.72 23.18 0.11 26.94

Sow 356 29.27 2.95 190.06 19.08 0.48 47.35

Summer

(June–Aug.)

Boar 2,270 86.34 4.02 222.01 31.66 0.09 13.46

Sow 477 104.87 8.99 187.22 29.23 0.20 15.14

Fall

(Sept.–Nov.)

Boar 4,476 81.61 2.89 237.02 24.33 0.11 30.05

Sow 0 0.00 0.00 0.00 0.00 0.00 0.00

Winter

(Dec.–Feb.)

Boar 5,120 127.02 4.37 246.39 18.28 0.08 33.04

Sow 914 32.44 4.30 400.64 19.72 0.22 33.36
Results 5

Boars and sows tended to cover more distance from 

0400 hours to 1000 hours or after 1600 hours to 0200 hours 

(fig. 4). Average air temperatures ranged between 16.8 °C at 

0500 hours and 31.1 °C at 1200 hours. The general tendency 

of travel by both genders is late afternoon until early morning 

(greatest average hourly distance covered by boar was 162 

meters [m] at 2300 hours and by sow was 96 m at 0600 hours) 

(fig. 4). 

A t-test with a Satterthwaite-test criterion for unequal 

variances (SAS Institute Inc., 2012) revealed that the average 

hourly movements between boars (99.72±2.12 m) and 

sows (51.57±3.47 m) were highly significant (P < 0.001). A 

one-way ANOVA utilizing Tukey’s HSD test (SAS Institute 

Inc., 2012) showed that average distance covered by wild 

pigs in winter (112.70±3.79 m) was greater (P < 0.05) than 

in the three other seasons: spring (84.10±4.65 m), summer 

(89.56±3.67 m), and fall (81.61±2.89 m).

Sex and season interacted for movement comparisons 

(P < 0.001); therefore, to distinguish which interaction 

effect differed from another, multiple comparison tests were 

conducted. All standard multiple comparison tests (Duncan, 

Student-Newman-Keuls, Tukey, Bonferroni) suggested 

that boar winter traveling patterns were greater than spring, 

summer, and fall movements, whereas sows showed 

significantly lower movements in spring and winter than in 

summer. Except for summer (when boars and sows did not 

exhibit any statistically significant differences [P = 0.056] in 

movement), there existed a very significant difference (P < 

0.001) in movement patterns between genders. 

Effects of air temperature on movement patterns of 

these wild pigs were evaluated by correlating average 

distances traveled within a 24-hour period and the 

corresponding average air temperature. Regardless of gender, 

the Pearson’s correlation coefficient (r = -0.74, P < 0.001) 

suggested a significant inverse relation between wild pig 

movements and air temperature (fig. 5; n = 24, r2 = 0.54 with 

P < 0.001). 

The air temperature effect separating genders yielded a 

significant negative correlation (r = -0.70, P < 0.001) among 

boars, but it was not significant (r = -0.34, P < 0.11) among 

sows. This finding suggests that sows are more tolerant of 

higher air temperatures or that sows move less than do boars, 

as documented by the Duncan multiple range test (n = 24, 

average distance traveled within 1 hour for boars was 98.34 m, 

compared to average distance traveled within 1 hour for sows, 

50.86 m, P < 0.05). 

0

5

10

15

20

25

30

35

0

20

40

60

80

100

120

140

Boar Sow Boar Sow Boar Boar Sow

Spring Summer Fall Winter

Average distance traveled per hour, in meters

Season

Average air temperature, in degrees Celsius

Distance, in meters

Temperature, in degrees Celsius

EXPLANATION

Figure 2. Average distance traveled per hour by collared wild pigs (Sus scrofa) and average air temperature by season during the 

2011–13 study in Louisiana and Mississippi.
6 Movements of Wild Pigs in Louisiana and Mississippi, 2011–13

Geospatial Analysis 

Although average movements of wild pigs, either 

regarding gender (boar or sow) or time (hourly, monthly, 

and [or] seasonally), showed a range of less than 200 m, the 

maximum distances traveled by individual wild pigs in specific 

circumstances differed greatly. Wild pigs traveled less than 

500 m 95 percent of the time, with less than 1.5 percent of the 

data indicating more than 1 kilometer (km) of distance covered 

within 1 hour (table 2). Maximum travel distance was as much 

as 6 km, with a maximum modal range of 2–3 km (fig. 6). 

The geospatial modeling environment (GME) program was 

used to provide information on the movements of wild pigs. 

Wild pig movement boundaries were analyzed by using the 

“GENMCP” function within the GME program (Beyer, 2014). 

The GENMCP function yielded a minimum convex polygon 

(MCP), which serves as a proxy of home range (where an 

animal lives and travels), of each collared wild pig. Regardless 

of marsh or nonmarsh area, average MCP for boars showed an 

area of 911 hectares (ha) (range of 47–3,689 ha), whereas for 

sows, it was 116 ha (range of 5.7–399 ha). 

Boars in Mississippi and Louisiana marsh habitat 

have similar MCP values (about 900 ha), whereas sows in 

Mississippi marsh habitat yielded an MCP value of about 60 

ha. Movements of collared boars in nonmarsh habitat (for 

example, forest and agricultural lands) in Louisiana indicated 

an MCP value four times greater than that for boars in marsh 

habitat. There were no data collected in this study from 

collared sows in marsh habitat in Louisiana or from collared 

boars in nonmarsh habitat in Mississippi, so we were unable to 

examine these relations. The MCPs suggest that when a wild 

pig is seen it will have a home range of approximately the 

area represented in the MCP values. Although MCPs have a 

tendency of overestimating the size of home range (Burgman 

and Fox, 2003), they provide a conservative approach to the 

risk assessment of potential infestations of wild pigs.

Monthly average of distance traveled per hour, in meters

Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Month

160

140

120

100

80

60

40

20

0

EXPLANATION

Symbol corrresponds to observed monthly average

Average of boar and sow

Sow

Boar

Figure 3. Monthly average of distance traveled per hour by collared wild pigs (Sus scrofa) during the 2011–13 study in Louisiana and 

Mississippi. 
Results 7

EXPLANATION

Distance traveled by boar

Distance traveled by sow

m, meter

0 m

40 m

80 m

120 m

160 m

0100

0200

0300

0400

0500

0600

0700

0800

0900

1000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

Figure 4. Average distance traveled by collared wild pigs (Sus scrofa) on an hourly basis during 24-hour periods and depicting diurnal 

effect in movement during the 2011–13 study in Louisiana and Mississippi.
8 Movements of Wild Pigs in Louisiana and Mississippi, 2011–13 Average distance per hour, in meters

160

140

120

100

80

60

40

Average air temperature, in degrees Celsius

18 20 22 24 26 28

EXPLANATION

Average hourly data point and time of day 

95-percent confidence band

Fitted regression line

0400

2300

2400

0800

2200 2100 2000

1800

1700

1200

1600

1000

0900

1100

1300

1400 1500

1900

0200

0700

0600 0100

0500

0300

0400

Figure 5. Regression with a 95-percent confidence band showing average distance per hour traveled by wild pigs (Sus scrofa) relative 

to average air temperature during a 24-hour period during the 2011–13 study in Louisiana and Mississippi.

Table 2. Distance traveled per hour by wild pigs (Sus scrofa) in interval frequency during the 2011–13 study in Louisiana and 

Mississippi.

[m, meters]

Distance (m) Frequency Percent Cumulative frequency Cumulative percent

0–25 9,921 59.50 9,921 59.50

25–50 1,710 10.26 11,631 69.76

50–100 1,645 9.87 13,276 79.62

100–200 1,431 8.58 14,707 88.20

200–500 1,278 7.66 15,985 95.87

500–1,000 452 2.71 16,437 98.58

Greater than 1,000 237 1.42 16,674 100.00
Discussion 9

Discussion

In this study, the feasibility of the Judas pig technique 

was successfully tested on only one boar in the Louisiana 

marsh; hence, the Judas pig technique is not central to this 

study. Interesting results, however, were obtained. This boar 

was used as a Judas pig, and 24 associated wild pigs were 

located in 1 day by tracking this boar until it was removed. At 

two other locations, the tracking data from the collared wild 

pigs were used to focus removal efforts, but the Judas pig 

technique was not strictly employed. The usage of Judas pig 

technique shows that it can be a valuable management control 

tool. 

Understanding wild pig range activity is crucial when 

developing a management plan to control populations. Home 

range expansion in a broad sense entails moving among 

locations to secure better resources and (or) environmental 

conditions. In the case of invasive wild pigs, these 

opportunistic movements translate into economic and natural 

resource losses. Telemetry data provide accurate locations 

of movement corridors and areas (hot spots) that are used 

intensively by wild pigs, thus providing useful information for 

wild pig management. Understanding wild pig movements at 

all levels is critical to responding to invasions.

Hayes and others (2009) used radio telemetry to assess 

movements of wild pigs in Mississippi. They reported that 

dry-season home ranges were larger (640 ha) than wet-season 

home ranges (300 ha) in a magnitude similar to this study. 

Schlichting and others (2012) in their satellite tracking study 

found MCPs in the more arid areas of Texas and Oklahoma 

of 4,100 and 2,900 ha, respectively. Chuelo (2012) reported 

Missouri wild pigs with an average home range of 2,400 ha. 

When compared to those in our study, wild pigs in the more 

arid climates have consistently greater home ranges.

We believe that one of the major factors contributing to 

the recent increase of wild pig populations in Louisiana and 

Mississippi is the aftermath of several catastrophic hurricanes 

that passed through these States within the last 10 years, 

including most notably hurricanes of 2005 (Katrina and Rita) 

and 2008 (Ike and Gustav) (B.L. Goatcher, USFWS, oral 

commun., 2010). For several years, following the passing of 

these hurricanes access was limited in coastal impact zones 

to wild pig hunters because of the downed timber and debris 

wracks (B.L. Goatcher, USFWS, oral commun., 2010). 

Additionally, hurricane and tornado thinning of woodlands 

and removing of forest canopies allowed sunlight to penetrate 

to the ground, encouraging dense growths of briars and deer 

peas (Vigna luteola) and providing additional escape cover 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Boar Sow Boar Sow Boar Sow Boar Sow

Winter Spring Summer Fall

3,518

2,440

3,833

385

3,208

1,442

6,098

Maximum distance traveled per hour, in meters

Season

Figure 6. Maximum distance traveled per hour by wild pigs (Sus scrofa) with respect to gender and season during the 2011–13 study in 

Louisiana and Mississippi.
10 Movements of Wild Pigs in Louisiana and Mississippi, 2011–13

and forage vegetation species that support wild pigs (B.L. 

Goatcher, USFWS, oral commun., 2010). Other significant 

contributions to population increases of wild pigs are 

presumed illegal relocations of these animals by humans and 

the fragmentation of land parcels (B.L. Goatcher, USFWS, 

oral commun., 2010).

Wild pigs in this study trended towards a crepuscular or 

nocturnal activity pattern, and home ranges were relatively 

limited compared to tracking studies elsewhere (911 ha for 

boars and 116 ha for sows). These limited home ranges, 

personal knowledge of past illegal relocations, and all 

published sources used in this research suggest that natural 

movements of wild pigs are not a major factor in the current 

range expansions. Any natural wild pig population and range 

changes are overshadowed by the rare but significant weatherrelated transfers (such as floods and hurricanes) that seed new 

populations and the illegal relocations and stocking of these 

animals by humans (Mayer, 2009).

It may be of interest to investigate why sows traveled 

more in summer and boars traveled more in winter. We 

postulate that, in general, sows in our populations move longer 

distances in summer because they are not hindered by neonatal 

piglets delivered during winter and spring. Comer and Mayer 

(2009) found that most populations show prominent peaks in 

farrowing in winter and spring, but farrowing varies depending 

on food availability and other environmental conditions. As 

for boars traveling longer distances in the winter, we speculate 

that they must travel longer distances to find mates because 

sows are less mobile during farrowing.

Future work on movements of wild pigs might include 

studying the distance a wild pig travels after being relocated 

from a capture site to a new location with wild pigs and 

without wild pigs or the amount of time it takes for a wild pig 

to reestablish a new home range. These answers will probably 

depend on the age of the animal, social rank of the animal, and 

quality and configuration of habitat on the landscape (such as 

marsh versus upland/agriculture). These studies could help 

management and lawmakers make more informed decisions 

regarding the presumed illegal transportation and control of 

wild pigs.

Summary

Wild pigs (Sus scrofa) are a major problem for land 

and resource managers in the United States because of the 

enormous amounts of damage that these animals cause to 

natural and man-made environments. This invasive species 

is found in large populations on public and private lands 

in most States. Their high reproductive potential, ability 

to adapt to numerous environments, destructive foraging 

habits, and potential to function as disease vectors make 

wild pigs a challenging and serious threat to environmental, 

human, and financially important resources in the United 

States.

From 2011 to 2013, the U.S. Geological Survey 

investigated spatial and temporal movements of wild pigs 

to establish an effective approach to wild pig controls in 

Mississippi and Louisiana; more information regarding wild pig 

populations, their habitat use, and movements at a landscape 

level is needed. Global Positioning System satellite hybrid 

radio telemetry devices were attached to 21 wild pigs that were 

captured with trained dogs and were released at the capture 

sites from August 3, 2011, until May 16, 2013. We collected 

16,674 hourly data points related to date, time, air temperature, 

and position from the collared wild pigs. Solar and lunar 

data, such as sun and moon phases and azimuth angles, were 

collected and analyzed; however, these data did not show any 

significant relations with movements among wild pigs. We 

found that, on average, the GPS-collared wild pigs traveled 

longer distances in summer and winter of 2011 and 2013 than in 

all four seasons of 2012. Relations of wild pig movements due 

to air temperature within and between seasons were analyzed. 

Movements were significantly correlated negatively with air 

temperature. Differences in movements between seasons and 

years were observed. On average, movements of boars were 

significantly greater than those of sows. Except for summer, 

there existed a very significant difference in movement patterns 

between genders. A significant inverse relation between wild 

pig movements and air temperature was observed between the 

genders.

Average home range, determined by using a minimum 

convex polygon as a proxy, was 911 hectares for boars, whereas 

average home range for sows was 116 hectares. Wild pigs in 

marsh habitat traveled lesser distances relative to those from 

more arid, nonmarsh habitats. Overall, results of this study 

indicate that wild pigs in Louisiana and Mississippi have small 

home ranges. These small home ranges suggest that natural 

movements have not been a major factor in the recent broadscale range expansion observed in this species in the United 

States.

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Hartley and others—Movements of Wild Pigs in Louisiana and Mississippi, 2011–13—OFR 2014–1241

ISSN 2331-1258 (online)

http://dx.doi.org/10.3133/ofr20141241